Featured image credit: RKK Energia/ ROSCOSMOS
Lift Off Time | December 13, 2021 – 12:07:00 UTC | 15:07:00 MSK |
|---|---|
Mission Name | Ekspress-AMU3 & AMU7 |
Launch Provider | Khrunichev State Research and Production Space Center |
Customer | The Russian Satellite Communication Company (RSCC) |
Rocket | Proton-M |
Launch Location | Launch Complex 200/39, Baikonur Cosmodrome, Kazakhstan |
Payload mass | 5,088 kg (11,210 lb) |
Where are the satellites going? | Geostationary Earth Orbit (GEO) |
Will they be attempting to recover the first stage? | No, Proton-M is not capable of recovery |
Where will the first stage land? | It will crash into the steppes of Kazakhstan |
Will they be attempting to recover the fairings? | No, Proton-M is not capable of recovery |
Are these fairings new? | Yes |
How’s the weather looking? | N/A |
This will be the: | – 2nd launch of Proton-M in 2021 – 13th launch from the Baikonur Cosmodrome of 2021 – 112th mission of Proton-M – 130th orbital launch attempt of 2021 |
Where to watch | Official livestream |
What Does All This Mean?
Russia is ready to launch the Ekspress-AMU3 and Ekspress-AMU7, two geostationary telecommunications satellites, for the Russian Satellite Communication Company (RSCC) which will be positioned in geostationary orbit (GEO) at 103° and 145° of east longitude, respectively. They will be launched atop a Proton-M launch vehicle. The rocket will lift off from Launch Complex 200/39, at the Baikonur Cosmodrome in Kazakhstan. This mission will mark the second flight of Proton-M in 2021, after the MLM Nauka mission which launched on July 21.
This flight follows one of the previous missions of the Proton-M rocket that launched the Ekspress-80 and Ekspress-103 communication satellites on July 31, 2020. Currently, the RSCC constellation consists of ten satellites.
Ekspress-AMU3 & AMU7
The Ekspress-AMU3 and Ekspress-AMU7 are commercial satellites manufactured by the Information Satellite Systems (ISS-Reshetnev Company, a part of ROSCOSMOS) and Thales Alenia Space Italia on the base of the middle-class satellite bus Express-1000N for the RSCC. Their main objective is to provide stationary and mobile communication services, digital television and radio broadcasting, high-speed Internet, and data communication in Russia and in CIS countries. The modular design of this platform ensures parallel and independent manufacturing and testing of the satellites and the bus.
Ekspress-AMU3 & AMU7 communication satellites (Credit: ROSCOSMOS) 
Ekspress-AMU3 & AMU7 communication integrated with the Briz-M (Credit: ROSCOSMOS/Yuzhny Space Center)
Specifications
These satellites operate in the C-, Ku-, Ka- and L- frequency bands and have a designed mission life of 15 years. The Ekspress-AMU7 carries 16 active transponders and 2 additional ones working in the C-band, 20 active transponders working in the Ku-band, and one active transponder working in the L-band. The Ekspress-AMU3, in turn, has 7 active transponders working in the C-band; in the Ku-band, it has reconfigurable architecture: it will have 8 active transponders for the first part of its mission and 22 active transponders for the second one, and two active transponders working in the L-band.
The satellites features devices for receiving the signal, its low-noise amplification and converting the frequency of the received signal according to the width of the channel working band, as well as retransmission of the received signal.
| Ekspress-AMU7 | Ekspress-AMU3 | |
| Satellite bus | Express-1000N | Express-1000N |
| Designated orbit | Geostationary Earth Orbit | Geostationary Earth Orbit |
| Lifespan | 15 years | 15 years |
| Position in orbit | 145° of east longitude | 103° of east longitude |
| Mass | 2,449 kg | 2,639 kg |
Ekspress-AMU 3 & AMU7 Mission Profile
For this mission, an energy-efficient pattern will be used, in which the rocket carries the satellite platform to the sub-orbital trajectory and then the Briz-M upper stage brings them to the geostationary transfer orbit (GTO), at a 49.3° inclination. The satellites have an electric propulsion unit onboard, which will move them from the transfer orbit to their designated GEO position. The Ekspress-AMU7 and Ekspress-AMU3 will separate after 17 hours 50 min and 18 hours 7 min after launch, respectively. After that, it will take about 56 days for the Ekspress-AMU7 and 59 days for the Ekspress-AMU3 to raise their orbit to a geostationary orbit.
What Is Proton-M?
Proton-M is a multi-use heavy-lift launch vehicle that first flew on April 7, 2001. It is capable to launch civilian and military satellites, as well as cargo missions to the ISS. This launch vehicle was developed and is manufactured by Khrunichev State Research and Production Space Center. Over the decades, several variants of the Proton rocket have been developed and flown over 400 times.
Compared to its ancestor, Proton-K, the Proton-M rocket has a new control system that not only enhances its power performance, but also improves its operational and environmental characteristics. For instance, it makes propellants utilization more efficient. It ensures that almost all fuel on the first stage of Proton-M burns up completely during ascent and the rocket crashes on land with empty tanks, which prevents contamination of the area.
The new system also provides a more controlled landing of the first stage. This has two benefits: easier debris recovery and reduced rent payment (the Baikonur Cosmodrome is located in Kazakhstan, where Russia leases the land). Moreover, it has larger payload fairings, which more than doubles available space for payloads.
The rocket consists of three stages, all of them are expendable. Proton-M can be accompanied by optional Briz-M or Block DM-03 fourth stages to insert payloads into a higher orbit.
Proton-M is about 58.2 meters (191 ft) in height and 7.4 meters (24 feet) in diameter. The vehicle’s total lift-off mass is approximately 705,000 kg (1,554,000 lb). The rocket’s payload lift capacity is 6,300 kg (13,850 Ib) to GTO and 3,300 kg (7,250 Ib) to GEO when flying with the Briz-M upper stage.
Stages
| First Stage | Second Stage | Third Stage | |
|---|---|---|---|
| Engine | 6 RD-276 | 3 RD-0210 and 1 RD-0211 | RD-0213 and RD-0214 |
| Total Thrust, kN / Ibf | 10,032 / 2,255,283, sea level | 2,354 kN / 529,200, sea level | 572 / 128,590 Ibf, vacuum |
| Specific Impulse, s | 288, sea level 316, vacuum | 320, sea level 327, vacuum | 325, vacuum |
| Burn time, s | 121 | 211 | 258 |
First Stage
The first stage (21.2 m in length) consists of a central cylindrical part, which is an oxidizer tank, and six side fuel tanks, each one of them is carrying an RD-276 engine, also known as an RD-275M engine. Unlike the four side boosters on Soyuz 2 rockets, the ones on Proton-M are not detachable.
One interesting fact about the Proton-M rocket is that its design was greatly affected by the logistics. For example, the diameter of its oxidizer tank is the maximum that can be delivered to the pad by rail.
The RD-276 engine runs on a hypergolic propellant that uses dinitrogen tetroxide (N2O4) as an oxidizer and unsymmetrical dimethylhydrazine (UDMH, (CH₃)₂N₂H₂) as a fuel. Each one of these engines has one combustion chamber and together they are capable of producing a thrust of 10,032 kN (2,255,283 Ibf) at sea level, with an ISP of 288 s at sea level and 316 s in a vacuum. A burn time of this stage is ∼121 s. The RD-276 engines can control thrust vector by swivelling tangentially up to 7° from their neutral position.
Second Stage
The second stage is 17.1 m long and is powered by three RD-0210 engines and one RD-0211 engine. The engines on this stage start their ignition sequence prior to stage separation. This process is called “hot fire staging”. That is why the second stage is joined to the first one through an interstage with a lattice structure and not through a closed one. This design allows the exhaust to escape and also reduces the mass of the interstage. Each one of these engines has one combustion chamber, runs on UDMH and N2O4, and burns for 211 s. A total thrust produced by this stage is 2,354 kN (529,200 Ibf) with an ISP of 320 s at sea level.
A render of the Soviet RD-0210 engine. (Credit: Caspar Stanley) 
A render of the Soviet RD-0211 engine. (Credit: Caspar Stanley)
Third Stage
Like the other two stages, the third one operates on UDMH and N2O4. It is 4.1 m long and is powered by one RD-0213 engine, and one RD-0214 engine that together form an RD-0212 engine. The RD-0213 engine has one combustion chamber and burns for 241 s, while RD-0214 has one combustion chamber, four nozzles, and a burn time of 258.3 s. An ISP of this stage is 325 s in a vacuum and a total thrust is 572 kN (128,590 Ibf).
Fourth Stage (Briz-M)
The upper stage consists of a central unit and an additional fuel tank. The Briz-M upper stage is hypergolic and features the S5.98M gas generator engine, capable of producing 19.6 kN of thrust.
The basis of the control system is the Mars-3M platform developed by the OKB Mars (located in Moscow, Russia). Starting from the launch on June 9, 2016, the Briz-M features an upgraded radio-telemetry system PIRIT-RBCs that is lighter than its predecessor (8 kg vs. 14 kg) and increases energy efficiency of the stage.
